CN107208352B

CN107208352B - Method for cutting out objects from an at least partially two-layered material web by means of a cutting device

Info

Publication number: CN107208352B
Application number: CN201580064497.6A
Authority: CN
Inventors: 贡纳尔·黑尔德
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-11-27
Filing date: 2015-11-10
Publication date: 2020-05-26
Anticipated expiration: 2035-11-10
Also published as: JP6594440B2; JP2018505324A; KR20170087861A; DE102014017501A1; EP3224404A1; ES2940576T3; KR102438240B1; CN107208352A; PL3224404T3; US20170356125A1; WO2016082915A1; EP3224404B1

Abstract

Method for cutting out objects from an at least partially two-layered material web by means of a cutting device, wherein the two material layers are connected to one another at least partially in a linear, strip-shaped and/or surface-shaped manner. The position of the respective object to be cut is detected in a contactless manner as a function of structural changes in the material, which are parts of the object that result from regions in the material web that are connected to one another in a linear, strip-shaped and/or planar manner. The detection of the position of the object is carried out in the material web at least as a function of a previously determined and stored pronounced and spaced-apart geometric partial shape of the linear, strip-shaped and/or area-shaped interconnected regions of the object.

Description

Method for cutting out objects from an at least partially two-layered material web by means of a cutting device

Technical Field

The invention relates to a method for cutting out (Ausschneiden) objects from an at least partially two-layered material web by means of a cutting device according to the preamble of claim 1.

The method provides, in particular, for bag-or pouch-shaped objects to be cut out of such a two-layer material web, to which also the blank for the airbag (Zuschnitte) belongs. The method is preferably applied in conjunction with a laser cutting device.

The material web from which the object is to be cut out consists of at least two material layers which are connected to one another at least in partial lines, strips and/or areas in the peripheral region of the respective object to be cut out. This connection can consist in gluing the two material webs, welding the two material webs or interlacing the two material webs. The interweaving of the two material webs is used in particular in the production of airbag blanks.

Background

In some applications, as is also the case in the production of airbag blanks, the parts must be cut very precisely in order to satisfy all safety-relevant aspects of the durability of the airbag when the airbag is used and deployed under high pressure, when the airbag blank is cut out of the material web, no interlaced or woven (verwrkten) regions of the two material layers of the material web are just allowed to be damaged and thus weaken the material web, not in which are interlaced or woven regions of the retaining eye (haloe ö sen) or the retaining strap (halolasthen) of the airbag which are placed in their final shape when the airbag is cut out, finally the airbag must be cut out precisely in accordance with the specification (vorgabin).

A problem in the cutting of objects from a material web and in particular from a two-layered material web is that the material web has deformations depending on the production process and due to the material and its treatment, which deformations can differ greatly both from material web to material web and also in the material web. If a cutting table based on a cutting device cuts out the objects with cutting data that are fixedly preset in the cutting device, the objects are not cut out along their preset contour in the material web due to the deformations in the material web.

In order to detect such deformations in the material web, one instead provides the material web with a marking fixedly associated with the object to be cut during the production of the material web. This mark is optically detected in the cutting device in order to determine from its position on the material web in which edge the material web is deformed. A correction value is derived from a deviation between a theoretical position (solposition) of the marking, which corresponds to the position of the marking during the production of the material web, and the actual position of the marking in the region of the cutting device. The cutting coordinates for cutting out the object are corrected on the basis of the correction values such that the object is cut out exactly along the predetermined contour despite the deformation of the material web.

A periodically repeating grid (Raster) formed by lines or crosses running longitudinally and transversely along the material web and which can be seen at points or crosses on the upper side of the material web is used, for example, as a marking. If this involves a woven (gewebte) or knitted (gewirkte) material web, then characteristic lines or marking lines are added to the material, which are distinguished in terms of color from the material web.

The marks are usually detected optically, i.e. without contact, and the position of the object in the material web is derived from the position (page, sometimes referred to as position, which is inverted to merely distinguish it from the "position") and the position of the mark, which is then assigned to the coordinates of the cutting device as cutting coordinates. Cutting out the corresponding object by means of the cutting device according to the cutting coordinates.

The method described above requires that in each case two or more layers of the material web must be provided with a marking, which must be printed on at least one side of the material web, or that the marking, in the case of a woven or knitted material web, must be added as a characteristic line. If defects, such as, for example, discontinuities (unsettigkeiten), occur during the embossing (Bedrucken) of the material web surface or during the introduction of the characteristic lines, a precise assignment of the object to be cut to the marking is not possible, which leads to defects. In addition, embossing the material web or adding characteristic lines is associated with additional expenditure and thus additional costs when producing the object.

Disclosure of Invention

The object of the invention is to provide a method of the type mentioned at the outset, which allows objects to be cut out of a material web of at least two layers in a precise location without the material web having to be provided with markings beforehand.

This object is achieved by a method having the features of claim 1. Advantageous embodiments of the method result from the dependent claims.

The method is characterized in that the location of the respective object to be cut is detected in a contactless manner as a function of a structural change in the material, which is a part of the object that is obtained as a result of regions in the material web that are connected to one another in a linear, strip-shaped and/or planar manner. The detection of the position of the object in the material web is carried out at least as a function of a previously determined and stored, pronounced (markanten) and mutually spaced geometric partial shape of the linear, strip-shaped and/or area-shaped interconnected regions of the object. At least a part of the structure in the material web obtained from the connected surface areas is thereby taken into account for detecting distortions and twists (Verdrehung) of the object in the material web due to distortions (Verzerrung) of the material web. A particular advantage of the method according to the invention is that it is not necessary to detect the entire geometry of the object or all of the regions of the profile in which the connected structures of the two material webs are located, although this is certainly possible; this, however, unnecessarily increases the computational effort to convert the detected coordinates into the cutting coordinates.

Preferably, therefore, only the geometric partial shapes of the connected structures are detected, and the geometric partial shapes are combined and/or supplemented with one another after their detection on the basis of the saved geometric shape of the object. The geometric shape of the parts of the object associated with the connected structures of the two material webs is determined beforehand. In particular, the geometric partial shape is a geometric partial shape which is particularly pronounced on account of its geometry. Such a pronounced geometric shape is, for example, a region with a strongly curved contour, a flap-like structure, irrespective of whether it is located in the region of the inner surface region or in the region of the outer contour of the object to be cut.

When the material web is located at the cutting station, the pronounced geometry can already be sufficient to derive therefrom the actual position of the object in the material web, in order to then cut the object with corrected cutting data corresponding to the distortions present in the material web.

As already mentioned, the significant geometric partial shape can be supplemented on the basis of the saved geometric and contour data of the objects, in order to determine the position of the respective object in the material web for the cutting process from the supplemented geometric shape of the respective object thereafter, and then to assign the cutting coordinates to the position of the object and to cut out the object with the cutting coordinates.

The contactless detection of the structural change in the material is preferably carried out by means of at least one photographic (fotografischen) device; this method is advantageous precisely when the woven or knitted structure is to be detected in the region in which the two material webs are connected. A photographic image is obtained just when the photographic device is positioned at a relatively large distance above the material web (this means at a distance of up to 1500mm, preferably about 800 to 1000 mm), in which image the woven or knitted structure to be detected is detected with a high resolution.

A plurality of individual images can be combined to form a total image (Gesamtbild), from which structural changes in the material are subsequently detected over a large area of the surface of the material web. The individual images form a panoramic image, wherein the individual images can also be joined to one another two-dimensionally in rows and columns (Reihen und Zeilen).

In order to reinforce the interconnected regions of the two layers of the material web with their significant (sich … abzeichen) contrast, the material web is illuminated. The structural change is thereby also more clearly shown. The illumination can be performed from the upper side, from which the photographed image is also taken. However, it is also proposed and preferred in certain applications to illuminate (durchleuchtet) the material web, preferably from the side of the material web opposite the photographic device, generally the underside of the material web, in order to detect without contact structural changes in the material.

It is also proposed to pass the material web through a scanning device on the entry side of the cutting device, which scans (absscan) the surface of the material web in a contactless manner with a small distance from the material web or scans the contrast obtained when the material web surface is irradiated through, preferably from the opposite side. Such a scanning device is arranged in a fixed association with the cutting coordinates or cutting table of the cutting device, so that the actual location of the deformations in the material web and thus of the linear, strip-shaped and/or planar interconnected regions (at least the geometric partial shapes thereof) of the object is detected and transmitted into the coordinates of the cutting device.

The described method also enables the detection of structural changes in the material which cannot be assigned to the parts of the object to be cut out where, for example, the two material layers are connected to one another in a linear, strip-shaped and/or planar manner and which can be checked as possible material defects. If a material defect is associated with a region of the object to be cut, the object is examined and it is determined whether the material defect relates only to optical aspects or to other aspects, for example, safety-related unacceptable aspects, for the object to be cut. Objects identified as defective are thereafter not cut out of the material web.

Drawings

Further details and features of the invention are obtained from the following description of embodiments with reference to the accompanying drawings. In the drawings:

fig. 1 shows a flow chart, referred to as main program, which represents the individual method steps of the method according to the invention,

fig. 2 shows a subroutine, which is added to the main routine of fig. 1,

fig. 3A to 3C show objects that are to be cut out of a material web in three method stages, which are assigned to the flowchart of fig. 1,

figure 4 shows a cutting device with which the method according to the invention can be carried out,

FIG. 5A shows a schematic view of a material web with a large number of objects in the material web being highlighted by structural changes in the material, an

Fig. 5B shows the object of fig. 5A as it is cut out by the device of fig. 4.

Detailed Description

The method according to the invention is based on the object being cut out of an at least partially two-ply material web 1 (as shown in fig. 5A and 5B) by means of a cutting device denoted by reference numeral 2 in fig. 4 and 5B. The material web 1 comprises at least two material layers which are connected to one another at least partially linearly, in strips and/or in a surface pattern in the peripheral region of the object 3 to be cut. Such objects 3 can be bags, pouches, pockets, but also more complex parts, such as for example airbags. Such an object 3 in the form of an airbag is shown in fig. 3A and its manufacture is described below with reference to the figures.

Airbags of the type generally designated by the reference numeral 3 below are usually produced from a woven or knitted material web which is formed from at least two material layers lying one on top of the other, which are interlaced and/or knitted in some regions. Such interwoven or woven regions of the airbag are represented in fig. 3A to 3C by black surfaces. The black surface partially forms a frame-shaped structure denoted by reference numeral 4, a web-shaped section, which is partially connected to the frame-shaped structure 4 and denoted by reference numeral 5, and an island-shaped section, which is located inside the frame-shaped structure 4 and denoted by reference numeral 6. At least the frame-shaped structure 4 is located inside the outer contour 7 of the airbag 3, along which the airbag is to be cut out of the material web 1.

Ideally, the connected structures of the material web 1 are oriented in the x-y direction of the rectangular coordinate system, as is also illustrated in fig. 3A on the basis of the dashed line 8. However, it is shown that the material web 1 has a deformation or torsion as it travels through the cutting table 9 for various reasons, such as manufacturing decisions, which can be represented, for example, by an extension or contraction in the x and/or y direction. This deformation can be clearly seen in fig. 5A.

In order to cut out the airbag 3 at the cutting station 9 despite the changed position due to the deformation of the material web 1 by means of the cutting device 2, the deformation must be taken into account, since otherwise there is the risk that the airbag 3 is not cut out along the outer contour line 7 and therefore damage to the safety-relevant interwoven or

woven structures

4 and 5 can occur in the region of the outer contour of the airbag 3. Not included is a strap-shaped section 5, in particular for fastening the airbag in a vehicle; such a strap-shaped section 5, in the region of which the two material layers of the material web 1 are interlaced or woven, can be brought into its final shape when the airbag 3 is cut out.

For the foregoing reasons, the method according to the invention is used, the flow of which is shown in the flow chart of fig. 1.

According to the method according to the invention, the position of the airbag 3 in the material web 1 is determined by contactless detection of structural changes in the material web 1, as is described in step 101. This structural change in the material web 1 is obtained as a result of the weave or weave structure visible on the surface of the material web 1, in the region of which the two material layers of the material web 1 are interlaced or woven with one another. Such a structural change can also be achieved by regions of the material web 1 in which the two material layers are glued or otherwise connected to one another.

The geometry of the object 3 to be cut out, i.e. the airbag to be cut out in the present case, is divided into geometric partial shapes in step 102, together with all the predetermined contour data and the structures (strukturengen), for example, frame-shaped structures 4, web-shaped segments 5, island-shaped segments 6 and outer contour lines 7. Such a geometric part shape is marked in fig. 3A and 3B by a rectangle 10. A particularly pronounced geometric region of the airbag 3 is preferably selected as the geometric partial shape 10; falling below it are, for example, a panel-shaped segment 5, an island-shaped segment 6, or at least a part thereof, and a part of the frame-shaped structure 4, which has a small radius of curvature.

It is illustrated, on the basis of x-y coordinates and a dashed line 8 as an example, that the structures visible in the material web are displaced by an angle 11, due to the deformation of the material web 1 along the cutting table 9 relative to the x-axis (see also fig. 5A), relative to the ideal location data in fig. 3A, on the basis of the interconnected regions of the material layers. Deformation also occurs with respect to the y-axis, although the deformation is not shown.

Thus, in step 103, a comparison of the position of the detected geometric section shape, which is indicated in fig. 3B by the reference numeral 4', 5' or 6' supplemented by a superscript dash, with the stored

geometric section shape

4, 5 or 6 (see fig. 3A) is carried out.

In step 104, it is determined whether the detected geometric partial shapes 4', 5', 6' can be assigned to the stored geometric shapes or to the stored geometric

partial shapes

4, 5, 6. If this is the case, the detected geometric partial shapes 10 (4 ', 5', 6 ') are connected to one another in step 105 on the basis of the stored data of the airbag structure in terms of calculation.

It should be noted that the geometric shape or structure 4' of the airbag 3, which is indicated by the rectangle 10, and only a part of the web-shaped and island-shaped segments 5', 6', are preferably detected, in order to thereby keep the computational effort for determining the position of the airbag 3 in the deformed material web 1 low. However, it is also possible to detect all the structure lines that appear in the structure of the material web 1 and to determine their location in the material web 1.

In step 106, the position of the object in the material web 1 is assigned to the cutting coordinate of the cutting device 2, and finally the respective object is cut out in step 107 using the cutting coordinate, in the case of the airbag shown in the figure, along the outer contour line 7, corresponding to the position of the object in the material web 1, which can be determined on the basis of the stored data of the airbag blank (see fig. 3A), as is shown in fig. 3C.

In order to detect structural changes in the material web 1 without contact, a camera system 12 is arranged on the entry side of the material web 1 into the cutting device 2; the material web 1 is additionally illuminated transversely (y-direction) to the direction of travel (x-direction) with a suitable light source 13 from the top in the area 14 marked in fig. 5A; however, it is also possible alternatively or additionally to illuminate the material web 1 with a light source 15 from below opposite the camera system 12, so that a relatively strong contrast between bright and dim areas can be detected by the camera system 12.

Fig. 3B and 3C show the detection of the position of a single airbag in the material web, while fig. 5A and 5B show the material web 1, over the length and width of which a large number of airbags 3 are distributed that are to be detected and cut out.

With the camera system 12, it is possible to detect larger regions of the material web 1 by combining individual images to form a total image in order to detect structural changes in the material web 1.

There is the option that in step 104 of the flowchart shown in fig. 1 it is concluded that the detected geometric shape 10 cannot be assigned to a stored geometric shape or geometric shape. If this is the case, the main routine of FIG. 1 branches to the subroutine shown in FIG. 2.

In the subroutine, in step 108, structural changes that cannot be assigned to the geometric shape or to the geometric partial shape are checked to determine whether they can be assigned to material defects and whether they are inside the object 3 to be cut, as shown in step 109 (step 110). If the structural change/material defect is not inside the object 3 to be cut, the structural change/material defect is ignored (step 111) because it cannot affect the object 3 to be cut outside the object 3 to be cut.

If it is determined in step 110 that the structural change/material defect is inside the object 3 to be cut, the object is marked as defective in step 112 and the cutting device 2 indicates in step 113 that the object is not to be cut (because of the defect) in order to thereby save machine run time.

Claims

1. Method for cutting out objects from an at least partially two-layered material web by means of a cutting device, in which at least two material layers are connected to one another in a partially linear, strip-shaped and/or surface-shaped manner at least in the peripheral region of the object to be cut out, wherein data associated with the position of the object in the material web are initially determined in a contactless manner, which data are associated with the coordinates of the cutting device as cutting coordinates, and wherein the respective object is cut out by means of the cutting device as a function of the cutting coordinates, characterized in that the position of the respective object to be cut out is detected in a contactless manner as a function of a structural change in the material, which is a part of the object that is obtained as a result of the regions in the material web that are connected to one another in a linear, strip-shaped and/or surface-shaped manner, wherein the detection of the position of the object in the material web is carried out at least as a function of a previously determined and stored pronounced and spaced-apart geometric partial shape of the regions of the object that are connected to one another in a linear, strip-shaped and/or surface form, wherein the structural change in the material web is obtained as a result of a woven or knitted structure that is visible on the surface of the material web, in the region of which the two material layers of the material web are interlaced or knitted to one another, or the structural change can be obtained by a region of the material web in which the two material layers are bonded to one another.

2. Method according to claim 1, characterized in that the geometrical part shapes are connected and/or supplemented to each other after their detection on the basis of the saved geometrical shape of the object.

3. The method according to claim 2, characterized in that the position of the respective object in the material web is determined for the cutting process from the complementary geometry of the respective object, in order to subsequently assign the cutting coordinates to the position of the object and to cut out the object using the cutting coordinates.

4. A method as claimed in any one of claims 1 to 3, characterized in that the contactless detection of structural changes in the material is carried out by means of at least one photographic device.

5. The method of claim 1, wherein structural changes in said material are detected from a plurality of individual images, said individual images being combined into a whole image.

6. The method of claim 1, wherein the material web is illuminated to contactlessly detect structural changes in the material.

7. Method according to claim 1, characterized in that the material web is irradiated for contactless detection of structural changes in the material.

8. Method according to claim 1, characterized in that detected structural changes in the material which are not assignable to the part of the object to be cut, where the two material layers are connected to one another in a linear, strip-shaped and/or planar manner, are examined as possible material defects.

9. The method according to claim 8, characterized in that the object associated with the material defect is not cut out of the material web.